An embodiment of the present invention is directed to a cylinder lock and key combination, wherein said cylinder lock comprises:
a housing having a cylindrical bore,
a cylindrical key plug being rotatably journalled in said cylindrical bore,
said key plug having a longitudinal, profiled keyway and means for locking the key plug against rotation in the cylindrical bore unless a correctly cut key blade is fully inserted into the keyway,
said keyway being oriented along a central plane and having a profiled cross-section being partly defined by a profile rib extending longitudinally along said key plug and having a predetermined cross-sectional contour along at least a part of its length, and wherein said key comprises a correctly cut key blade having:
a cross-sectional profile fitting into said keyway, and
a profile groove formed by a lower side wall and an upper side wall and extending longitudinally along the correctly cut key blade, said profile groove having a cross-sectional profile configured to accommodate said profile rib of the keyway when the correctly cut key blade is being inserted into the lock, wherein:
said lock comprises a blocking mechanism with at least one blocking element reaching into said keyway in the vicinity of said profile rib, said profile rib being provided with at least one longitudinally confined cut-out portion accommodating said at least one blocking element and each said at least one blocking element forming a movable portion of said profile rib,
said at least one blocking element is movable from a first blocking position, in which a first projecting portion of a cross-sectional profile of the at least one blocking element extends outside and below the cross-sectional contour of said profile rib, into a second blocking position, in which a different, second projecting portion of said at least one blocking element extends outside and above the cross-sectional contour of said profile rib and is accommodated by at least one local recess formed in the upper side wall of the profile groove of the correctly cut key blade,
one of said first projecting portion and said second projecting portion of the at least one blocking element always extending outside the contour of the profile rib, seen in a vertical direction,
the insertion of the correctly cut key blade causes the movement of said at least one blocking element from said first blocking position into said second blocking position,
said first and second projecting portions of said at least one blocking element are non-symmetrical in shape;
wherein a vertical dimension of an outer portion of said profile groove between said lower side wall and said upper side wall is smaller than a vertical dimension of said at least one blocking element except at said at least one local recess where a vertical dimension of said outer portion is larger than the vertical dimension of said at least one blocking element, said vertical dimension of said outer portion of said at least one local recess extending between non-symmetrical and non-parallel upper and lower side walls thereof;
said upper and lower side walls of said outer portion of said at least one local recess being adapted in shape so as to accommodate said non-symmetrical first and second projecting portions of said at least one blocking element; and
said profile groove, with its at least one local recess, being configured to enable said at least one blocking element to perform an elevational movement to said second blocking position so as to be accommodated in said at least one local recess, when the correctly cut key blade is being inserted into said key way of the key plug but blocks the full insertion of any other key blade not being provided with said at least one local recess.
Such lock and key combinations are generally known, e.g. from the U.S. Pat. No. 5,715,717 (Widén). The profile groove or grooves in the key, and the corresponding profile ribs in the keyway of the lock, will provide great possibilities to vary the cross-sectional profile of the key, which is a great advantage.